DE102005034938B4 - Electromagnetic hydraulic valve - Google Patents

Abstract

Electromagnetic hydraulic valve (1) having a magnet armature (8) guided longitudinally movably in an armature guide (9) and actuating a valve tappet (15) extending in a valve housing (14) which controls the connection between connection openings (28, 29) formed in the valve housing (14) , 30) for hydraulic means controlled by the valve stem (15) in operative connection with one or more sealing bodies (22, 23) corresponding to one or more on the valve housing (14) supported sealing sleeves (17, 18), wherein the hydraulic valve ( 1) comprises a means for separating dirt particles, characterized in that the means in a between the armature guide (9) and the connection openings (28, 29, 30) arranged intermediate bottom (31), with an inner circumferential surface (16) of the valve housing (14) closes hydraulically sealing, wherein the valve housing (14) for the purpose of separating ferromagnetic dirt particles from a magnetizable W Substance exists.

Description

Field of the invention

The invention relates to an electromagnetic hydraulic valve with a longitudinally movably guided in an armature guide armature, which operates a running in a valve housing valve tappet. This controls the connection between formed in the valve housing connection openings for hydraulic means by the valve stem is in operative connection with one or more sealing bodies, which correspond with one or more supported on the valve housing sealing sleeves, wherein the hydraulic valve has a means for the separation of dirt particles.

Background of the invention

Hydraulic valves which, in order to ensure a permanent functioning of the hydraulic valves themselves or of downstream components, have means for separating dirt particles from the hydraulic medium are known in the prior art. These dirt particles pass as suspended particles in the hydraulic fluid in the hydraulic valve and have their origin on the one hand in so-called residual dirt that accumulates in the production of an internal combustion engine mainly in the form of metallic particles and can not be completely removed by complex cleaning measures. On the other hand, these dirt particles are created by permanent abrasion of moving components during operation of the internal combustion engine. Thus, the functionality of horizontally installed hydraulic valves can be endangered by excessive penetration of dirt particles between the armature and its armature guide. The resulting stiffness of the armature usually leads to a significant impairment of the Umschaltdynamik the hydraulic valve and manifests itself in a reduced and / or sharply fluctuating gradient of the hydraulic fluid pressure to be controlled. In extreme cases, reaching into the armature guide dirt particles cause a complete failure of the hydraulic valve as a result of a jamming armature.

So in the considered as generic DE 196 31 631 A1 proposed an electromagnetic hydraulic valve whose pressure port has a screen filter for inlet-side separation of dirt particles. However, this method has some disadvantages, which are explained below.

First of all, it is not taken into account that production-related dirt residues in the hydraulic valve itself as well as dirt particles which arise due to the operational cooperation of moving components in the hydraulic valve can lead to a functional impairment of the hydraulic valve as well as downstream components over their intended service life.

Furthermore, the separation efficiency of the sieve filter depends on its mesh size or the size of the passage openings. In this respect, penetration of foreign dirt particles into the hydraulic valve is only limited, but not completely prevented. This restriction is particularly disadvantageous in hydraulic valve designs, in which the hydraulic valve flows through hydraulic fluid coming from a plurality of connecting lines. For example, in the case of a 3/2-way valve to achieve the (limited) effect, it would at least be necessary to provide both the pressure port P and the working port A with a filter element, since in a second switching position of such a hydraulic valve the hydraulic fluid from the working line A coming in the direction of the tank port T flows. However, the installation of a second filter element is associated with a correspondingly high and costly construction.

In addition, to retain very small particles, a fine or ultra-fine filter is provided, however, generates an undesirably high pressure loss of the hydraulic fluid at the inlet and in the case of the aforementioned 3/2-way valve with two filter elements even when exiting the hydraulic valve. This pressure loss also increases with the loading of the filter with dirt particles over time.

The DE 101 95 791 B4 discloses an electromagnet having an improvement in abrasion resistance. A fluid containment chamber is substantially coaxial with a plunger chamber and disposed on a side opposite a center support with the plunger chamber disposed therebetween. On the outer peripheral side of the rod, a first bearing for separating the plunger chamber from the fluid collecting chamber is provided.

The DE 44 31 459 A1 shows a arranged in the interior of a solenoid valve magnetic core, which is penetrated by a guided in a bearing ram. Molded onto the underside of the magnetic core in a connecting element made of plastic with an integrally arranged valve seat. Due to the design and arrangement of connecting element and bearing the manufacturability of the solenoid valve is simplified and improves its functional properties.

The DE 43 05 987 C1 shows a solenoid valve with a vertically above the valve seat and Closing body arranged drive, wherein mounted on the valve rod between the armature and valve stem guide a dirt-deflecting collar and in the collar facing the end face of the valve stem guide an annular recess is provided as a dirt trap.

The DE 41 11 987 A1 shows a solenoid valve having a cylindrical armature having two cylinder sections of different diameters. This magnet armature is stored in a guide insert. The guide insert has two sections, wherein the portion of the guide insert receiving the cylinder section of smaller diameter has a hexagonal cross-section. The cylinder portion of larger diameter of the armature is facing the cooperating with the magnetic pole member. This design of magnet armature and guide sleeve achieves both a large pole surface and a secondary air gap with low magnetic resistance.

The DE 91 07 436 U1 shows a solenoid valve with an acted upon by a magnet armature, for actuating the valve in a valve chamber protruding plunger, wherein the armature is arranged in a oiled with pressure medium armature space. The solenoid valve has a separating chamber connecting the valve chamber with the armature space for sedimentation of the dirt particles present in the pressure medium volume in the transition region between the valve chamber and the armature space.

Object of the invention

The invention is therefore based on the object to avoid these disadvantages and to provide an electromagnetic hydraulic valve of the aforementioned type, the means for the separation of the dirt particles permanently ensure the functioning of the hydraulic valve. In particular, the armature guide should be largely protected from penetrating dirt particles in order to effectively prevent a temporary or permanent jamming of the magnet armature in the armature guide. The hydraulic valve should also be possible to produce as inexpensively.

Summary of the invention

According to the invention the object is achieved by the features of claims 1 and 10, while advantageous developments and refinements can be found in the dependent claims.

According to the characterizing part of claim 1, the means for separating the dirt particles in a arranged between the armature guide and the connection openings intermediate bottom, which closes with an inner circumferential surface of the valve housing hydraulically sealing. In this case, the valve housing consists of a magnetizable material for the purpose of separating ferromagnetic dirt particles. The functionality of the thus formed hydraulic valve is permanently ensured in particular by the fact that the hydraulic valve is flowed through primarily in the region of the connection openings with hydraulic fluid, while the magnet armature and its armature guide are shielded by the intermediate bottom. Thus, dirt particles that pass through the connection openings in the interior of the hydraulic valve - and unless they are transported with the flow of hydraulic fluid out of the valve - kept away from the armature and its leadership by the shielding effect of the false bottom. Since at the same time the valve housing is magnetizable and is magnetized during operation of the hydraulic valve by the action of the energized electromagnet, the predominantly ferromagnetic dirt particles are deposited on the side facing away from the magnet armature of the intermediate bottom of the inner surface of the valve housing. A further transport of the deposited dirt particles in the direction of the armature is then prevented in particular in a horizontally installed hydraulic valve, characterized in that the intermediate bottom with the inner circumferential surface of the valve housing terminates hydraulically sealing.

A particularly effective separation of the ferromagnetic dirt particles to the magnetized valve housing while keeping the particles away from the immediate vicinity of the valve stem can be achieved particularly effective in that the intermediate bottom is made as a single part and consists of a non-magnetizable material. The hydraulically sealed connection of this item with the valve body can be done in known ways positive, non-positive or cohesive as well as in combination of these types of connections. As non-magnetizable material of the intermediate floor thus formed, it is expedient to provide, in addition to plastic, an austenitic corrosion-resistant steel, such as, for example, X5CrNi1810.

The manufactured as a single part intermediate floor can also be formed as a thin-walled and cup-shaped annular sleeve having a cylindrical outer circumferential surface and a bottom which engages around the valve stem with an outer circumferential surface concentric opening. In this case, the annular sleeve is pressed over the outer circumferential surface in the inner circumferential surface of the valve housing so that the open side of the annular sleeve faces the armature. An advantage of this design of the false floor is the most cost-effective too finished and easy to install ring sleeve in the valve body. Another inventive idea provides that the bottom of the annular sleeve is cone-shaped in such a way that an annular space for separated dirt particles is formed between an outer side of the base facing away from the magnet armature and the inner lateral surface of the valve housing. The thus designed annular sleeve thus unfolds as it were an optimal storage effect, since the low flow velocities in the annulus favor a local whereabouts of the deposited dirt particles.

In a further development of the invention, the hydraulic valve should be designed as a 3/2-way valve, wherein the connection openings serve as a pressure port P, working port A and tank port T. In particular, the 3/2-way valve can be both functionally reliable and cost produced in that the valve stem is made as a molded plastic and protruding strips, with which it is guided on the side facing the armature side of the intermediate bottom in the valve housing. Here, the sealing body of the valve stem to run on the side facing away from the magnet armature of the intermediate bottom and having conical and facing sealing surfaces which interact alternately with valve seats which are integrally formed on the cup-shaped and pressed into the valve housing sealing sleeves.

Furthermore, at least one overflow cross section in the direction of the magnet armature should remain between the valve tappet and the intermediate bottom. Such Überströmquerschnitt serves on the one hand for volume and pressure equalization within the hydraulic valve during strokes of the armature and the valve lifter. On the other hand, sufficient lubrication of the magnet armature moved longitudinally in the armature guide is ensured by the passage of hydraulic medium. Although a transport of dirt particles in the direction of the armature is not excluded during an overflow of hydraulic fluid, but it is due only to the above-described shielding effect of the false bottom only a negligible amount of dirt particles whose ferromagnetic portion also predominantly on the magnetized inner surface the valve housing would deposit beyond the false floor.

The hydraulic valve should preferably be used to control hydraulically displaceable actuators of a variable valve train of an internal combustion engine. Such actuators are known to those skilled in the field of variable valve trains, inter alia, as hydraulically actuated coupling means, as for example in camshaft adjusters, variably switchable cam of a camshaft or for switching or switching off gas exchange valves with switchable cam followers in the form of switchable plungers, levers or support elements Use come. In the hydraulic control of such coupling means, it depends on the highest possible, slightly fluctuating and reproducible gradient of the hydraulic medium pressure in the working line when switching between the two positions of the hydraulic valve. This is due in the case of the switchable cam or the switchable cam follower in that the switching operation of the coupling means must always be completed successfully in the only very short time of a cam base circle phase for all involved cam followers.

A task-oriented solution is also given by the features mentioned in the characterizing part of claim 10. These are explained above and relate in combination to a particularly preferred embodiment of the hydraulic valve according to the invention, whose risk against jamming of the armature due to penetrating into the armature guide dirt particles is at least considerably reduced by simple means. In addition, a high, slightly fluctuating and permanently reproducible gradient of the hydraulic fluid pressure is ensured by the permanently uniform and low-friction longitudinal guidance of the armature in its armature guide and the valve stem.

Brief description of the drawings

In the accompanying drawings, the electromagnetic hydraulic valve according to the invention is shown using the example of a 3/2-way valve. Show it:

1 a longitudinal section through the 3/2-way valve,

2 the detail Z out 1 and

3 the section AA according to 1

Detailed description of the drawing

Out 1 goes an electromagnetic hydraulic valve 1 which functions as a 3/2-way valve 2 formed and used to control a variable valve train of an internal combustion engine, not shown. The hydraulic valve 1 consists of an electromagnet 3 with one in a bobbin 4 made of plastic cast coil winding 5 in a magnet housing 6 , As upper magnetic pole 7 for a magnet armature 8th one also serves in the bobbin 4 cast anchor guide 9 in which the magnet armature 8th simultaneously guided longitudinally movable. A lower magnetic pole 10 is by a collar 11 formed into a flange area 12 with a screw connection 13 for fastening the hydraulic valve 1 at a suitable point of the internal combustion engine passes.

In the ring collar 11 of the lower magnetic pole 10 is still a the electromagnet 3 facing upper portion of a valve housing 14 added. The valve housing 14 is tubular and consists of a magnetizable material which during operation of the hydraulic valve 1 as a result of the electromagnetic effect of the energized electromagnet 3 is magnetized. The valve housing 14 accommodates itself to the magnet armature 8th subsequent valve tappet 15 and two cup-shaped and in an inner circumferential surface 16 of the valve housing 14 pressed-in sealing sleeves 17 . 18 , The valve lifter 15 is made as a molded plastic and, as in 3 clearly recognizable, with three staggered by 120 ° bars arranged 19 in the inner circumferential surface 16 of the valve housing 14 guided longitudinally movable. Furthermore, the valve tappet is 15 by one on the magnet armature 8th fitting front side 20 and by one on the front side 20 molded and formed in the hollow cylindrical magnet armature 8th protruding centering pin 21 in loose operative connection with the magnet armature 8th , Starting from the strips 19 the valve tappet tapers 15 and points to the magnet armature 8th opposite side two sealing bodies 22 . 23 with cone-shaped and facing sealing surfaces 24 . 25 on. The sealing surfaces 24 . 25 work alternately with valve seats 26 . 27 together, on the sealing sleeves 17 . 18 are formed.

The control of hydraulic fluid flow through the hydraulic valve 1 takes place in the manner described below. In 1 is a first switching position of the hydraulic valve 1 shown. In this first switching position is the coil winding 5 in energized state, so that the armature 8th taking along the valve lifter 15 due to the magnetic attraction of the lower magnetic pole 10 attracted and shifted in its direction. In this position, the sealing surface lies 24 of the first sealing body 22 at the valve seat 26 the magnet armature 8th facing sealing sleeve 17 at. At the same time, the sealing surface 25 of the second sealing body 23 to the valve seat 27 the magnet armature 8th facing away sealing sleeve 18 spaced. Thus, a hydraulic fluid flow between a pressure port P, by an axial mouth 28 the tubular valve housing 14 is formed, and a working port A, by a between the sealing sleeves 17 . 18 radially arranged opening 29 in the valve housing 14 is formed, set. In this switching position of the hydraulic valve 1 Consequently, a communicating with the working port A actuator of the variable valve train is supplied with pressurized hydraulic fluid, for example, to put a travel or an adjustment angle.

To return the actuator to its original position is the energization of the coil winding 5 off. In this de-energized state of the electromagnet 3 No electromagnetic forces act on the armature 8th , so that this together with the force-loaded by ram pressure of the hydraulic fluid valve lifter 15 in the direction of the second switching position of the hydraulic valve 1 is relocated. This switching position is achieved when the sealing surface 25 of the second sealing body 23 in the valve seat 27 is located so that the hydraulic fluid flow between the pressure port P and the working port A is interrupted. Because at the same time the sealing surface 24 of the first sealing body 22 from the valve seat 26 is spaced, a hydraulic fluid flow between the working port A and a tank port T is allowed. The tank connection T is like the working connection A as a radial opening 30 in the valve housing 14 trained and connects the hydraulic valve 1 with a pressureless hydraulic fluid reservoir of the internal combustion engine. Consequently, the hydraulic medium volume corresponding to the travel or setting angle of the returning actuator can flow away via the tank connection T.

Penetration of dirt particles into the dirt-sensitive guide gap between the anchor guide 9 and the armature 8th is particularly in the horizontal installation case of the hydraulic valve 1 by the shielding effect of one between the anchor guide 9 and the connections P, A, T in the valve housing 14 arranged intermediate floor 31 largely prevented. The intermediate floor 31 is in the in 2 shown detail Z shown enlarged and in the embodiment as a single part 32 in the form of a thin-walled and cup-shaped annular sleeve 33 educated. This is with a cylindrical outer circumferential surface 34 between the bars 19 of the valve lifter 15 and the tank port T in the inner circumferential surface 16 of the valve housing 14 hydraulically sealing pressed. Furthermore, the annular sleeve 33 a floor 35 on, the valve tappet 15 with a to the outer surface 34 concentric opening 36 game-related and consequently friction-free and without leadership function encompasses. Because of the soil 35 the annular sleeve 33 is cone-shaped and the open side of the annular sleeve 33 the magnet armature 8th is facing, is between a magnet armature 8th opposite outside 37 of the soil 35 and the inner circumferential surface 16 of the valve housing 14 an annulus 38 educated. Due to the operation of the hydraulic valve 1 magnetizing valve housing 14 become the predominantly ferromagnetic dirt particles from the valve body 14 attracted and may be in the area of the annulus 38 deposit. In addition, there is the annular sleeve 33 made of a non-magnetizable material, to a deposit of dirt particles. in the immediate vicinity of the valve stem 15 and thus a transport of accumulated dirt particles in the direction of the magnet armature 8th counteract.

As a suitable material for the annular sleeve 33 An austenitic corrosion-resistant steel of, for example, the quality X5CrNi1810 is provided. Alternatively, the annular sleeve 33 However, also be made of plastic, in which case the connection with the valve housing 14 preferably also positive parts, such as a clip connection would have. Alternatively, however, the possibility should not be ruled out, the annular sleeve 33 to produce from a permanent magnet material.

Like from the 3 shown section AA can be seen, are located between the opening 36 the annular sleeve 33 and the valve lifter 15 three overflow cross sections 39 for hydraulic fluid in the direction of the armature 8th , These overflow cross sections 39 result from longitudinal grooves 40 in the valve lifter 15 angular offset to the strips 19 run. The overflow cross sections 39 are on the one hand to pressure and volume compensation of the hydraulic fluid during the switching operation of the armature 8th and the valve lifter 15 required and on the other hand ensure adequate lubrication of the armature guide 9 with hydraulic fluid. Although through these overflow cross sections 39 a transport of dirt particles in the area of the magnet armature 8th and the anchor guide 9 is not excluded, it is ensured according to the invention that the majority of the dirt particles in the region of the annular sleeve 33 and the magnetized valve housing 14 deposits and remains there or from the hydraulic valve 1 is rinsed out again. In this respect, the hydraulic valve according to the invention 1 Compared to the prior art with a simple and inexpensive means to be implemented as far as possible before temporary or permanent terminals of the armature 8th in the anchor guide 9 Protected due to penetrating dirt particles.

LIST OF REFERENCE NUMBERS

1

hydraulic valve

2

3/2-way valve

3

electromagnet

4

bobbins

5

coil winding

6

magnet housing

7

upper magnetic pole

8th

armature

9

armature guide

10

lower magnetic pole

11

collar

12

flange

13

Verschraubungsöffnung

14

valve housing

15

tappet

16

Inner surface area

17

sealing sleeve

18

sealing sleeve

19

strip

20

front

21

spigot

22

sealing body

23

sealing body

24

sealing surface

25

sealing surface

26

valve seat

27

valve seat

28

axial mouth

29

opening

30

opening

31

false floor

32

detail

33

ring sleeve

34

Outer casing surface

35

ground

36

opening

37

outside

38

annulus

39

overflow cross

40

longitudinal grooves

P

pressure connection

A

working port

T

tank connection

Claims (10)

Electromagnetic Hydraulic Valve ( 1 ) with one in an anchor guide ( 9 ) longitudinally movably guided magnet armature ( 8th ), one in a valve housing ( 14 ) extending valve tappets ( 15 ), which controls the connection between in the valve housing ( 14 ) formed connection openings ( 28 . 29 . 30 ) controls hydraulic means by the valve stem ( 15 ) in operative connection with one or more sealing bodies ( 22 . 23 ) with one or more on the valve housing ( 14 ) supported sealing sleeves ( 17 . 18 ), whereby the hydraulic valve ( 1 ) has a means for separating dirt particles, characterized in that the means in one between the anchor guide ( 9 ) and the connection openings ( 28 . 29 . 30 ) arranged intermediate floor ( 31 ), which is provided with an inner circumferential surface ( 16 ) of the valve housing ( 14 ) hydraulically sealing, wherein the valve housing ( 14 ) for the purpose of separating ferromagnetic particles of a magnetizable material. Hydraulic valve according to claim 1, characterized in that the intermediate floor ( 31 ) as a single part ( 32 ) is made, not one magnetizable material and with the valve housing ( 14 ) is positively connected, positively or materially connected. Hydraulic valve according to claim 2, characterized in that the item ( 32 ) is made of austenitic stainless steel. Hydraulic valve according to claim 2, characterized in that the item ( 32 ) as a thin-walled and cup-shaped annular sleeve ( 33 ) with a cylindrical outer circumferential surface ( 34 ) and a floor ( 35 ), the valve stem ( 15 ) with an outer surface ( 34 ) concentric opening ( 36 ) engages, is formed and over the outer circumferential surface ( 34 ) in the inner circumferential surface ( 16 ) of the valve housing ( 14 ) is pressed so that the open side of the annular sleeve ( 33 ) the magnet armature ( 8th ) is facing. Hydraulic valve according to claim 4, characterized in that the bottom ( 35 ) of the annular sleeve ( 33 ) is cone-shaped such that between a magnet armature ( 8th ) facing away from outside ( 37 ) of the soil ( 35 ) and the inner surface ( 16 ) of the valve housing ( 14 ) an annulus ( 38 ) is formed for deposited dirt particles. Hydraulic valve according to claim 1, characterized in that the hydraulic valve ( 1 ) as 3/2-way valve ( 2 ), wherein the connection openings ( 28 . 29 . 30 ) serve as pressure connection (P), working connection (A) and tank connection (T). Hydraulic valve according to claim 1, characterized in that the valve tappet ( 15 ) is made as a molded plastic body and projecting strips ( 19 ), with which it on the magnet armature ( 8th ) facing side of the intermediate floor ( 31 ) in the valve housing ( 14 ), while the sealing bodies ( 22 . 23 ) of the valve tappet ( 15 ) on the magnet armature ( 8th ) facing away from the intermediate floor ( 31 ) and conical and facing sealing surfaces ( 24 . 25 ), which alternately with valve seats ( 26 . 27 ) which act on the cup-shaped and pressed into the valve housing sealing sleeves ( 17 . 18 ) are formed. Hydraulic valve according to claim 1, characterized in that between the valve tappet ( 15 ) and the intermediate floor ( 31 ) at least one overflow cross section ( 39 ) in the direction of the armature ( 8th ) remains. Hydraulic valve according to claim 1, characterized in that the hydraulic valve ( 1 ) for controlling hydraulically displaceable actuators of a variable valve train of an internal combustion engine is used. Hydraulic valve according to the preamble of claim 1, characterized by the following features: - the means for separating dirt particles consists in a between the armature guide ( 9 ) and the connection openings ( 28 . 29 . 30 ) arranged intermediate floor ( 31 ), which with an inner circumferential surface ( 16 ) of the valve housing ( 14 ) hydraulically sealing, wherein the valve housing ( 14 ) for the purpose of separating ferromagnetic particles of a magnetizable material; Between the valve stem ( 15 ) and the intermediate floor ( 31 ) remains at least one overflow cross section ( 39 ) in the direction of the armature ( 8th ); - the intermediate floor ( 31 ) is made of austenitic corrosion-resistant steel and as a thin-walled and cup-shaped annular sleeve ( 33 ) with a cylindrical outer circumferential surface ( 34 ) and a floor ( 35 ), the valve stem ( 15 ) with an outer surface ( 34 ) concentric opening ( 36 ) engages, formed and over the outer circumferential surface ( 34 ) in the inner circumferential surface ( 16 ) of the valve housing ( 14 ) so pressed in that the open side of the annular sleeve ( 33 ) the magnet armature ( 8th facing); - the valve lifter ( 15 ) is made as a molded plastic body and has projecting strips ( 19 ), with which he is on the magnet armature ( 8th ) facing side of the annular sleeve ( 33 ) in the valve housing ( 14 ), while the sealing bodies ( 22 . 23 ) of the valve tappet ( 15 ) on the magnet armature ( 8th ) facing away from the intermediate floor ( 31 ) and conical and facing sealing surfaces ( 24 . 25 ), which alternately with valve seats ( 26 . 27 ) which act on the cup-shaped and pressed into the valve housing sealing sleeves ( 17 . 18 ) are formed; - the hydraulic valve ( 1 ) is a 3/2-way valve ( 2 ) for controlling hydraulically displaceable adjusting elements of a variable valve train of an internal combustion engine, wherein the connection openings ( 28 . 29 . 30 ) serve as pressure connection (P), working connection (A) and tank connection (T).

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